Preheat the oven to 350°F (177°C). Line a 12-cup muffin pan with cupcake liners. This recipe yields about 15 cupcakes, so you'll have a 2nd batch.

Whisk the flour, baking powder, and salt together in a large bowl. Set aside.

Using a handheld or stand mixer fitted with a paddle attachment, beat the butter, sugar, and lemon zest together on medium-high speed in a large bowl until creamed, about 3 minutes.

Add eggs and vanilla extract, and then beat on medium-high speed until combined, about 1 minute.

Add the dry ingredients and then turn the mixer on low speed and slowly pour in the milk and lemon juice. Beat until just combined. Fold in the floured blueberries. Do not overmix.

Pour/spoon the batter into the liners—fill only 2/3 full to avoid spilling over the sides. Bake for 18–21 minutes. Allow the cupcakes to cool completely before frosting.

In a large bowl using a handheld or stand mixer fitted with a whisk or paddle attachment, beat the cream cheese and butter together on medium speed until smooth, about 2 minutes.

Add confectioners' sugar, vanilla extract, and salt and beat on low speed for 30 seconds, then turn the mixer up to medium-high speed and beat for 2 full minutes.

Frost cooled cupcakes and top with optional garnish, if desired.

Cover and store leftover cupcakes in the refrigerator for up to 5 days.